Search

• Research on land-atmosphere interactions covers a large breadth of disciplines. • Silos between research areas are reinforced by increasingly complex approaches. • This issue integrates research across the soil-vegetation-atmosphere continuum. • New funding opportunities are needed to support this trans-disciplinary work. • Coordinated networks are expensive but will facilitate transformational knowledge. To help bridge science topics related to land-atmosphere interactions, we organized a virtual special issue in this journal (Agricultural and Forest Meteorology [AFM]) entitled, "Land-Atmosphere Interactions: Integrating Surface Flux with Boundary Layer Measurements." The motivation for the special issue was driven by existing disciplinary barriers between research areas that all address land-atmosphere interactions. In particular, it addressed research silos between those who study features of the land surface, surface fluxes (including water, energy, and trace gases), atmospheric boundary layer growth and thermodynamics, and atmospheric composition and aerosols. The special issue sought to bring these communities together to integrate multiple observations across the soil-vegetation-atmosphere continuum with the aim of 1) improving broader understanding of land-atmosphere interactions, feedbacks, and coupling, 2) fostering new collaborations between atmospheric and surface flux scientists, and 3) identifying new paths for integrative research. Here, we provide an overview and synthesis of the special issue. [ABSTRACT FROM AUTHOR]

• We investigated effects of tree species diversity on rainfall partitioning. • Rainfall partitioning was highly dependant on tree species identity. • Non-additive diversity effects were detected in mixed plots. • Tree species diversity did not affect rainfall partitioning directly. • Species richness affected rainfall partitioning indirectly by increased basal area. Rainfall partitioning is a key process in forest ecosystems, affecting evaporation, transpiration and water storage in the canopy, litter and soil. Although rainfall partitioning has been well studied in forest ecosystems, less is known about how rainfall partitioning is modified by tree species diversity. To disentangle the effects of tree species identity and diversity on rainfall partitioning, we installed 128 rain gauges in an experimental plantation, located in Zedelgem (Belgium), part of a large, multi-site forest diversity experiment in Belgium (FORBIO). With these rain gauges, we monitored throughfall for a full year, with a temporal resolution of two weeks. Based on these data, we analysed identity (i.e. whether throughfall is species-specific), non-additive (i.e. whether throughfall in mixtures is different from the expected amounts based on monocultures) and richness effects (i.e. how species richness affects throughfall). First of all, we found that rainfall partitioning highly differed between tree species, due to pronounced species identity effects. The presence of Pinus sylvestris [pine] was always associated with lower throughfall. Year-round throughfall was, for example, the lowest in mixtures of pine and Tilia cordata [lime] (43.8 ± 14.5% of the open-field rainfall) and monocultures of pine (48.6 ± 11.8%). Additionally, non-additive effects were significant, leading to a 10% decrease of rainfall reaching the forest floor in mixtures compared to the expected throughfall based on measurements in monocultures. Tree species richness effects on rainfall partitioning acted indirectly, mostly via an increased basal area in mixed stands. Our findings suggest that mixing tree species leads to a higher than expected reduction in throughfall, which lowered soil moisture in mixed plots. Whether this reduced throughfall and soil moisture affects ecosystem functioning remains to be quantified. [ABSTRACT FROM AUTHOR]